FI83526B - FOERFARANDE FOER FRAMSTAELLNING AV BIOLOGISKT AKTIVA HEPTAPEPTIDER. - Google Patents

Abstract

There are provided peptides of the formula X-Val-Pro-Leu-Gly-Trp-A-Y wherein X represents a hydrogen atom or a terminal nitrogen protecting group, A represents a neutral L- alpha -amino acid residue and Y represents OH, NH2 or a group of the formula OR, NHR, NR2 or NHNHR' wherein R represents a C1-C11 alkyl group optionally substituted, a C7-C14 aralkyl or a phenyl group and R' represents H, any of the groups which R may represent or a protecting group. Pharmaceutically or veterinarily acceptable salt of these peptides are also provided, as are pharmaceutical or veterinary compositions containing peptides or their salts. The peptides which can be prepared by classical solution synthesis, display useful activity on the central nervous system and are active as growth promotors.

Description

83526

METHOD FOR THE PREPARATION OF BIOLOGICALLY ACTIVE HEPTAPEPTIDES - FOR A PREPARATION OF BIOLOGICALLY ACTIVE HEPTAPEPTIDIDES

The invention relates to a process for the preparation of biologically active peptides, their pharmaceutically or veterinarily acceptable salts and mixtures of substances.

The notations and abbreviations in this specification are commonly used in peptide chemistry, cf. Biochemistry (1975) 14, 449.

More specifically, the invention relates to the preparation of peptides having the general formula: X-Val-Pro-Pro-Leu-Gly-Trp-A-Y (I) wherein X represents a hydrogen atom, A represents methionyl and Y represents a hydroxy group, an amino group or a methoxy group.

The preparation of salts of the peptides of the general formula (I): with pharmaceutically acceptable acids or bases is also within the scope of the invention. Such acid addition salts can be derived from a variety of inorganic and organic acids. remove such as sulfur, phosphorus, salt, hydrogen bromide, iodine ·· * nitrogen, nitrogen, sulfamide, lemon, milk, fir grape, oxalate, maleic, amber, wine , cinnamic, acetic, trifluoroacetic, benzoic, salicylic, gluconic and ascorbic acids. Base addition salts can be derived from various inorganic and organic bases, such as sodium and calcium hydroxide, diethylamine, trimethylamine and dicyclohexylamine.

The synthesis of the peptides of the invention can be performed by classical methods. The synthesis mainly comprises successive condensations of the protected amino acids or pepids in question. "The condensations are carried out in such a way that the resulting peptides have the desired series of seven amino acid residues. The following groups can be used to protect amino groups: benzylcarbonyl, t-butoxycarbonyl, o-phenyl, trifyl, formyl, formyl, formyl. 4-Methoxybenzyloxycarbonyl, 9-fluorenylmethoxycarbonyl, 3,5-dimethoxy <', CX, - dimethyl Benzyl oxycarbonyl and methylsulfonylethoxycarbonyl The following groups can be used to protect the carboxy group: methyl, ethyl, tb utyl, benzyl, p-nitrobenzyl and fluorenyl methyl.

Condensation between the amino group of one molecule and the carboxyl group of another molecule to form a peptide bond can be performed by an activated acyl derivative such as an anhydride mixture, azide or activated ester, or by direct condensation between the free amino group and the free carboxy group alone in the presence of a condensing agent. or in combination with an anti-racemizing agent, e.g. N-hydroxysuccinimide or 1-hydroxybenzotriazole. The condensation can be performed in a solvent such as dimethylformamide, pyridine, acetone tril, tetrahydrofuran or N-methyl-2-pyrrolidone. The reaction temperature may range from -30 ° C to ambient temperature. The reaction time is usually 1 to 120 hours. The synthetic formula, protecting groups and condensing agents are chosen so as to avoid the risk of racemization.

Deprotection reactions are performed by methods known per se from polypeptide chemistry. For example, when preparing peptides in which Y represents an OR group, the starting point is the C-terminal amino acid esterified with a suitable alcohol. Peptides in which Y represents an OH group can be prepared, e.g., by hydrolysis of peptides in which Y represents an OR group. Peptides 3,83526 in which Y represents one of the groups NH4 »NHR, or NR2s can be prepared by ammonolysis from the corresponding esters or using as starting material a C-terminal amino acid amidated with a suitable amine. The hydrazido or substituted hydrazido derivatives of the invention are prepared by condensing an N-protected peptide or amino acid with an appropriately substituted hydrazine, e.g. reacting the protected peptide or amino acid hydrazide with a suitable alkylating agent, e.g. an alkyl chloride, or a suitable acylating agent such as benzyl chloroformate, t-butyl chloroformate, di-t-butyl dicarbonate or adamantyl fluoroformate.

The final condensation in the preparation of the peptide of the invention preferably takes place between the compound of formula II: X-Val-Pro-Pro-OH and the compound III: H-Leu-Gly-Trp-AY, wherein A, X and Y have the same meaning as above except that X does not does not represent a hydrogen atom and Y does not represent a hydrazine group, in the presence of a condensing agent, e.g. dicyclohexylcarbodiimide, alone or in combination with an anti-racemizing agent, or an anhydride mixture, an active ester or azide of a compound of formula II as defined above.

For growth promoters, there is no mention of heptapeptides describing the Trp excess at the 6-position characteristic of the invention.

The compounds of general formula (I) have an interesting growth-promoting effect in animals, as determined by both the i.n_vivo- __ ^^ _ t_ro method 1 in the protein synthesis of liver tissue (described by K. Kämmerer and A. Dey-Hazra (1980) Vet. Med.

:: Nachr. Nr. 2, 99-112) and dose-dependent weight gain and the effect of administration after subcutaneous or oral administration.

4 83526 ^ n_y i y o -i n_yy t r o-k or_Pr o t e i ^ n i sy n t e e s.i

Growth experiments were performed over a 4-week period using groups of 6 male rats (Wistar, Hagemann, Extertal) divided into subgroups of three rats in macrolon cages as wood chips as a medium.

Water and nutrition (Altrom 1321 standard diet containing 19% crude protein): to your liking.

The peptides of general formula I were administered in solution subcutaneously daily at doses of 10, 50 and 100 ng / kg using normal saline as a diluent (starting from a stock solution of 100 ng / ml).

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Homogenize 3 g of liver into 9 ml of TKM buffer-sucrose solution, cooled on ice in a Potter homogenizer at 600 rpm for 2 min. I drive; centrifuged at 10,000 g for 20 min at 4 ° C in an ultracentrifuge. time, decant the supernatant = initial mucosal cell fluid.

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After the amount of protozoal cell fluid protein was calculated by the biuret method, the protein concentration was adjusted to 1 mg / ml with TKM buffer. It was then diluted twice with distilled water to give 0.25 mg of protein per ml of adult solution.

Then 0.15 ml aliquots of the reaction agent and 0.05 ml of 14 (50 mcg) pyruvate kinase solution as well as 0.1 ml of C-amino acid mixture (= 1μ0ΐ) were added. The volume of the mixture was then 1 ml in each case.

After heating for 35 minutes at 37 ° C in a water bath, precipitation of the protein was performed by adding 2 ml of trichloroacetic acid (10%). The precipitate was washed with several trichloroacetic acid polyads and then centrifuged (3600 g / 5 min) until the supernatant was free of radioactivity.

The residue was dissolved in 1.0 ml of Lumasolve and left overnight at 37 ° C until clear.

The preparation was measured in a PRIAS liquid scintillation counter PL (1.0 ml + 5 ml liquid).

The method is described in detail in Kämmerer's article mentioned above.

TABLE0_1 ^ - Results of measurements of protein synthesis in liver tissue of male rats after a treatment period of 4 weeks (daily subcutaneous injection).

[..........! ..... '................ I

1 Treatment agent Dose j CPM I Group of reference rats j | (ng / kg) 'j Untreated Treated j Eg 1 i 10 14072! +17.7 +36.1 ... | i ': | Compound (TK7) 50 j 15093 +26.2 +46.0; | I 100! 16180 +35.3 +56.5

Ex. 2 10 13377 +11.9 +29.4

Compound (TK7D) 50 j 14280 +19.4 +38.2 j 100; 16866 +41.0 +63.2 Untreated - j 11958 - - comparison group Treated ver-, - 10366; -13.6 tail group ____ CPM = reading per minute.

6 83526

The control group

Rats treated by subcutaneous administration of physiological sodium chloride solution show a 13.6% reduction in the effect of protein synthesis compared to the untreated control group.

This difference can be statistically confirmed.

The measured degrees of protein synthesis of the compounds prepared according to Examples 1 and 2 differ significantly from both control groups.

Furthermore, the increase in protein synthesis is proportional to the doses.

The compounds of general formula (I) also have interesting endocrine effects, such as an effect on the secretion of prolactin and luteinizing hormone. In addition, they have an effect on the central nervous system, especially as a sedative-hypnotic agent. In fact, they are able to cause a decrease in innate activity in rats as well as cause it to behave sleepily.

Another embodiment of the present invention is to provide a method of preparing veterinary compositions for administration to animals and enhancing their growth and nutritional efficacy, comprising admixing a compound of general formula I or a veterinarily acceptable salt thereof with a veterinary diluent or carrier.

In veterinary medicine, a carrier is an edible substance to which the peptides of the general formula I are added in order to facilitate the uniform distribution of such peptides in the nutrients. The active peptide is adsorbed, impregnated, or enters the surface of the edible material so that 7,83526 active peptide is dispersed and physically transported.

A carrier suitable for veterinary use may also be a plastic particle to which the compounds of general formula I are added and from which the active ingredient is released in a delayed manner.

The compounds of this invention and the compositions containing them are particularly suitable for animals raised for human consumption, such as poultry, ruminants, pigs and rabbits.

Although all types of poultry — e.g., chickens, turkeys, geese, ducks, guinea fowl, pheasants, and quails — show an increase in growth rate and improved nutritional efficiency, the method is particularly useful in broiler chickens and turkeys.

For ruminants, e.g. cattle, sheep and goats, the method is particularly suitable for cattle, e.g. young bulls.

The method of administering a compound of general formula I or a mixture thereof containing the present invention according to the invention is mixed with about 2-40 mcg / ton, preferably 4-20 mcg / ton, of animal feed.

Animals are allowed to eat freely during the growing season.

There are different nutrient doses for different animal species. The compounds or mixtures of the general formula (I) prepared according to the invention can be used in connection with all known known doses of nutrients.

The term "nutrient intake" refers to food administered to animals and is not intended to limit the invention. Preferably, the compound of general formula I or a mixture containing it is mixed thoroughly with the nutrient dose so that it is uniformly dispersed throughout. Any of the known nutrient doses can be used in the practice of this invention and is not intended to limit the invention. Nutrient doses are formulated so that the animals for which they are intended receive them with their main nutrients, minerals, vitamins, supplementary feed, etc. The preparation of these doses is customary for nutritionists.

Another method of administering the compounds of general formula I is a subcutaneous pellet, e.g. by injecting a peptide of the present invention in the form of a pellet into an animal, the substance being released daily at 1-100 ng / kg, preferably 10-50 ng / kg.

Thus, the invention is not intended to be limited to any particular mode of administration.

Preferred peptides according to the invention are the following:

H-Val-Pro-Pro-Ley-Gly-Trp-Met-OH

H-Val-Pro-Pro-Leu-Gly-Trp-Met-OMe H-Val-Pro-Pro-Ley-Gly-Trp-Met-NH2

The following examples illustrate the invention. Benchmarks were determined on precoated silica gel 60 F K (Merck) plates with a plate thickness of 0.25 mm and a length of 20 cm using the following development methods:

System A: benzene / petrol (60-80) / ethyl acetate = 70/10/40 parts by volume

System B: benzene / ethyl acetate / acetic acid / water = 100/100/20/10 volumes (upper phase)

System C: benzene / ethyl acetate / acetic acid / water = 100/100/40/15 parts by volume (upper phase)

System D: n-butanol / acetic acid / water = 4/1/1 parts by volume. "E. Merck" is a trademark of 9,83526 TLC analyzes were performed at a temperature between 18-25 ° C: Rf values can therefore vary by + 5%. Melting points were determined in open capillaries on a Tottol apparatus and are uncorrected. Most derivatives soften and decompose before melting. Solvents for crystallization, precipitation or grinding are indicated in parentheses.

High-voltage paper electrophoresis is performed on a Pherograph-Original-Frankfurt Type 64 apparatus with Schleicher et Schiill paper no. 2317 at pH 1.2 (formic acid: acetic acid: water = 123: 100: 177 parts by volume) at 1600 volts (40 V / cm), and at pH 5.8 (pyridine: acetic acid: water = 450: 50: 4500 parts by volume) at a voltage of 1400 V (32.5 V / cm). The products were characterized by their variability in Glu at pH 1.2 (E_ _) and pH 5.8 (E_ _). In the following 1.2- b. o The symbols and abbreviations mentioned above are used in the characters.

AcOEt, ethyl acetate; BOCC t-butoxycarbonyl; Bzl, benzyl; d, decomposition; DMF, dimethylformamide; Et 2 O, diethyl ether; HCl / THF, hydrogen chloride in tetrahydrofuran; iPr 2 O, diisopropyl ether; iPrOH, isopropanol; Me, methyl; MeOH, methanol; NMH, N-methylmorpholine; PE, petroleum ether; THF, tetrahydrofuran; TLC, thin layer chromatography.

-f- Es i mark ^ 1 H-Val-Pro-Pro-Leu-Gly-Trp-Met-OH: Preparation of HCl (XIII) Step_1 ^ BCC-Trp-Met-OMe (I)

To a solution of 30.43 g (100 mmol) of BOC-Trp-OH in 200 mL of anhydrous THF was added 11.2 mL (100 mmol) of V; NMH and 9.9 mL of ethyl chloroformate sequentially at -12 ° C. After stirring at this temperature for 2 minutes, a cold solution containing 19.96 g (100 mmol) of HCl.H-Met-OMe was added. Dekker et al., J. Biol. Chem. 180, 155 (1949) and 11.2 mL of NMM (100 mmol) in 150 mL of DMF. The reaction mixture was stirred for 45 minutes at -12 ° C and 90-103526 minutes at 0-15 ° C, then the salts were removed by filtration and evaporated in vacuo. The residue was dissolved in ethyl acetate and washed several times successively with 1M saturated sodium chloride solution of citric acid, 1M sodium bicarbonate and water, the organic layer was dried over anhydrous sodium sulfate and the solvent was removed in vacuo.

Compound I was obtained 39.12 g (87% yield)

PO

iPrOH / iPr20 / from PE; mp. 95-97 ° C, [α] D = -25.1 ° (c = 1,

MeOH); Rf 0.73; Rf 0.76.

A D

Step 2 HCl-Trp-Met-OMe (II) 39.00 g (86.75 mmol) of BOC-Trp-Met-OMe (I) were dissolved in 390 ml of formic acid at room temperature. After complete removal of BOC (TLC monitoring) the solvent was evaporated in vacuo at 30 ° C. The residue was dissolved in methanol cooled to 0 ° C and 34.7 mL (104.1 mmol) of 3M HCl / THF-Liu was added. The solvents were removed in vacuo to give a quantitative amount of 33.48 g of compound II as an oil. Rfp 0.71,

El, 2 ° '28

Step_3_L BOC-Gly-Trp-Met-OMe (III) Starting from 15.20 g (86.75 mmol) of BOC-Gly-OH and 33.48 g (86.75 mmol) of HCl. Trp-Met-OMe (II) and acting in the same manner as in Step 1 except that chloroform was used instead of ethyl acetate to isolate the product gave 26.27 g (60% of theory) of compound III from ACOEt / Et 2 O / iPr 2 O: m.p. 140-145 ° C; [α] D = -30 ° (c = 1, MeOH);

Rf. 0.27; Rf 0.56; Rf 0.77.

ABC

Step_4 ^ HC1.H-Gly-Trp-Met-OMe (IV) From 26.20 g (51.71 mmol) of BOC-Gly-Trp-Met-OMe

(III) and proceeding as described in Step 2, 21.76 g (95% of theory) of compound IV were obtained.

11 83526 iPrOH / iPr ^ Orsta; mp. 195 ° C (d); l_ ° Q2 ° D = ~ 12.9 ° C (c = 1,

MeOH); Rf 0.49 E 0.84.

Step_5 ^ BOC-Leu-Gly-Trp-Met-OMe (V)

To a solution of 12.16 g (48.76 mmol) of BOC-Leu-OH in 120 mL of anhydrous THF was added sequentially 5.5 mL (48.76 mmol) of NMM and 4.8 mL of . (48.76 mmol) ethyl chloroformate at -12 ° C. After stirring at this temperature for 2 minutes, a cold solution containing 21.6 g (48.76 mmol) of HCl.H-Gly-Trp-Met-OMe (IV) and 5.5 ml (48.76 mmol) of mmol) of NMM in 100 ml of DMF. The reaction mixture was stirred for 1 hour at -12 ° C and for 2 hours at 0-15 ° C, then filtered off from the salts and evaporated in vacuo. The crude product was purified by flash chromatography on silica gel (Merck) 0.040-0.063 mm eluting with AcOEt. 18.13 g (60%) of AcOEt / Et 0 / PE were obtained.

^ PO

theor.) compound V: m.p. 110 ° C [α] D = -31.6 ° (c = 1, MeOH);

Rf 0.14; RfB 0.54.

Step_6_L HC 1. H-Leu-G ly-Trp-Met-OMe (VI) 18 g (29.04 mmol) of BOC-Leu-Gly-Trp-Met-OMe (V) were dissolved in 290 ml of a saturated solution of hydrogen chloride in glacial acetic acid, ... to which were added 18 ml of anisole and 9 ml of 2-mercaptoethanol.

After 30 minutes at room temperature, the BOC was completely removed and the solvent was removed in vacuo at 30 ° C. The crude product was purified by column chromatography on silica gel (Merck) 0.040-0.063 mm eluting with chloroform: me-. tanolilla = 8: 2. 12.44 g (77% of theory) of iPrOH / iPrO were obtained.

* * ^ 20) of compound VI: m.p. 170 ° C; Qcy] ^ = -9.9 ° (c = 1,

MeOH); Rf ^ 0.62; E 0.71.

BOC-Pro-Pro-OBzl (VII)

To a solution of 21.52 g (100 mmol) of BOC-ProOH in 200 mL of anhydrous THF were sequentially added 11.2 mL of NMM and 13.3 mL of isobutyl fluoroformate at -10 ° C.

83526

After stirring at this temperature for 3 minutes, a cold solution containing 24.17 g (100 mmol) of HCl. H-Pro-OBz1 (J. Ramachandran and CH Li, J. Org. Chem. (1963) 28, 173) was added. ) and 11.2 ml (100 mmol) of NMM in 150 ML of DMF. The reaction mixture was stirred for 1 hour at -10 ° C and for 2 hours at 0-15 ° C, then separated from the salts by filtration and evaporated in vacuo. The residue was dissolved in ethyl acetate and washed several times successively with 1M saturated sodium chloride solution of citric acid, 1M sodium bicarbonate and water. The organic layer was dried over anhydrous sodium sulfate and the solvent was removed in vacuo to give 34.21 g (85% of theory) of compound VII as an oil. Rf 0.62.

3

Step_8 _; _ HCl. H-Pro-Pro-OBzl (VIII) 34.21 g (85 mmol) of BOC-Pro-Pro-OBzl (VII) were dissolved in 342 ml of saturated hydrogen chloride solution in acetic acid at room temperature. After 30 minutes, the BOC was completely removed and the solvent was removed in vacuo. 21.60 g (75% of theory) of compound VIII were obtained from iPrOH / AcOE; RfD 0.32, E 2 1.12.

Step_SK BOC-Val-Pro-Pro-OBzl (IX)

Starting from 13.79 g (63.45 mmol) of BOC-Val-OH and 21.5 g (63.45 mmol) of HCl. H-Pro-Pro-OBzl (VIII) and acting as shown in step 7, 22.28 g (70% of theory) of compound IX were obtained as an oil after purification by column chromatography on silica gel (Merck) 0.040-0.063 mm eluting with ethyl acetate-methanol = 98: 2.

Step_lCK BOC-Val-Pro-Pro-OH (X) 22.28 g (44.42 mmol) of BOC-Val-Pro-Pro-OBzl (IX) dissolved in 150 ml of methanol were hydrogenated at room temperature and at ambient pressure when 4.46 g of 10% palladium on carbon were present. The catalyst was removed by filtration and the solution was concentrated in vacuo. The residue was dissolved in 13,83526 ethyl acetate and concentrated in vacuo. Dilution with diethyl ether gave 10.98 g (60% of theory) of compound X: m.p. 184-1900 ° C * J = -149.9 ° (c = 1, MeOH); Rf 0.24; rf

U EC

0.53; E _ 0.51.

D i O

Step_111 BOC-Val-Pro-Pro-Ley-Gly-Trp-Met-OMe (XI) Starting from 9.10 g (22.12 mmol) of BOC-Val-Pro-Pro-OH (X) and 12.30 g (22.12 mmol) of HCl. H-Leu-Gly-Trp-Met-OMe (VI) and acting as described in step 5, but eluting with ethyl acetate containing an increasing amount of methanol from 5% to 30% during chromatographic purification, 16.16 g (80% of theory) of compound XI iPrOH / iPr 0 were obtained, m.p. 184-190 ° C 20 O = -98.9 ° (c = 1.0, MeOH); Rf 0 0.13; Rfc 0.58.

Step_l2_ ^ BOC-Val-Pro-Pro-Leu-Gly-Trp-Met-OH (XII) 5.00 g (5.48 mmol) BOC-Val-Pro-Pro-Leu-Gly-Trp-Met-OMe: a. ·: (XI) was dissolved in 20 ml of methanol and saponified with ... 10 ml of 1M sodium hydroxide for 2 hours at room temperature. The solution was diluted with water, partially concentrated in vacuo, cooled to 0 ° C, acidified (pH 2) with 5M aqueous hydrochloric acid and then extracted several times with ethyl acetate. The organic layer was washed with neutral saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. After removal of the solvent, 3.99 g (81% of theory) of compound XII were obtained: m.p.

194-2000 ° C (d): [α] D = -102.9 ° (c = 1.0, MeOH); Rfc 0.34; E5 0.18 Glu.

H-Val-Pro-Pro-Leu-Gly-Trp-Met-OH.HCl (XIII) Starting from 3.85 g (4.28 mmol) BOC-Val-Pro-Pro-Leu-Gly-Trp-Met -OH (XII) and acting as described in step 6 gave 3.05 g of compound XIII as a crude product from iPrOH / iPr 2 O. The crude product was then purified on DEAE-Sephadex A-25 (trademark) using a 0.02M solution of ammonium acetate in pH 6.7 as eluent. After lyophilization from acetic acid, the product was redissolved in acetic acid and treated with 6 ml of a saturated solution of hydrochloric acid in acetic acid. The solution was poured into diethyl ether. 2.57 g (72% of theory) of compound XIII were obtained: m.p. 150 ° C; D>] 20 = -90.5 ° (c = 1, MeOH); Rf 0.30; E 058 Glu.

E s i ^ merkk i _4

Growth test in pigs

The growth experiment was performed over a period of 4 weeks, using a group of 7 castrated male (hybrids) divided into subgroups and placed in cages with a flat bottom. Pigs were fed growth medium (Höveler, normal-type, without supplements), 1 kg per day, throughout the experiment. Water was given freely. Weights were recorded weekly. The test results are shown in the following table.

Group Animal treatment agent Dosage Parameters _______ number ______________________________________ __ 1 _________ 2 ______________-_____________-_________ 5ΗΗ! ΠίίΕ_Ε®ίΕ2 2 2 2 NaCl physiol. 0.1 ml / kg Food intake __________________________________________1 u t us________ 3 3 TK-7 (e.g. l) 50 ng / kg Food efficacy (r.p.) (ng food / kg weight gain ______________________________________________ _______ i5 83526

Score

Group 12 3 Treatment - NaCl physiol. TK-7 (Example 1)

Dose tus_ ^ ng / kgX ________ 2 __________ 2 ________________-________

Initial weight (kg) 12.5 14.8 11.7

Weight after 1 week 14.0 16.3 15.2

Weight after 2 weeks 16.0 18.5 17.8

Weight after 3 weeks ______________ 19a3 _______ 20 ± 5 _____________ 20 ^ 7 _______

Weight gain kg 6.8 5.7 9.0

Weight gain,% 54.4 38.5 76.9 from comparison group _____________- 16z2 ____________ + 32 ^ 4 _______

Consumption (kg)

Dietary Efficacy 3.09 3.68 2.33 4 ^ _ £ ® ££ §iiH £ Zi2E! M ££ M _____________ + 19 ^ 1 ____________- 24 ^ 6 _______ Daily physiological saline injection produced a reduction in weight gain compared to the untreated group. Instead of a decrease in growth due to injection stress, animals receiving daily injection of TK-7 showed a clear increase in weight. The effect of diet shows weight gain results.

Claims (3)

A process for preparing biologically active peptides of the formula X-Val-Pro-Pro-Leu-Gly-Trp-AY, (I) wherein X is a hydrogen atom, A is a methionyl and Y is a hydroxy group, amino group or methoxyl group, or pharmaceutically or veterinarily acceptable salts of these peptides, characterized in that the predetermined amino acids or derivatives in a defined order and / or peptide fractions, which contain these amino acids or derivatives in a defined order, are condensed into a defined peptide either in the manner that the end of the carboxyl group or of the amino group is activated for a peptide bond and other groups are temporarily protected, or optionally the protection is removed and / or the resulting peptide is changed to its site which is pharmaceutically or veterinarily acceptable. Process according to claim 1, characterized in that it consists of condensing a compound of formula II X-Val-Pro-Pro-OH (II): selectively, when dicyclohexylcarbodimide is present, or I "-" condensation of mixed anhydride of the compound, an activated ester of its azide, with a compound having the general formula III H-Leu-Gly-Trp-AY (III) wherein X, A and Y are the same as in claim 1, except that X is not H and Y not NHNH ?, and, if necessary, an embodiment with respect to the obtained peptide by removing the peptide protecting group of claim 1. "3. Process according to claim 1 or 2 for the preparation of a compound H-Val-Pro-Leu-Gly-Trp-Met-Y • where Y is a hydroxy or methoxy group, characterized in that the BOC group is removed from the Boc group. Val-Pro-Pro-Leu -: 61y-Trp-Met-Y, wherein Y is the same as before, with chlorine - hydrogen in acetic acid or tetrahydrofuran.